Previous designs for thermionic converters have all used single current carrying leads as connections to the emitter and collector electrodes. To be removed the total current of each converter cell must flow through the electrodes at the location of the electrical leads. As converter cell design is growing larger, large electrode areas are constructed and the large currents which flow in the electrodes present problems in the form of ohmic losses and magnetic fields. Large currents require thick electrodes to minimize electrical losses. These electrodes are expensive, particularly at emitter temperatures where material resistance is high and refractories are needed. Thick electrodes result in large temperature drops across the electrodes, giving higher peak temperatures and greater stresses. Large currents in the electrode produce a large magnetic field in the gap which causes the electrons in the plasma to travel in curved paths and thereby reduces the current reaching the collector. At present these defects limit converter size and geometry. Large currents in a converter are desirable because they permit the use of high resistance, metallic closures instead of ceramic metal seals.
It is therefore an object of this invention to provide an improved thermionic converter.
Another object of this invention is to provide an improved means of coupling electrical leads to the electrodes of thermionic converters.